Currently, a pixel structure, in a sensor of a phone camera, includes a micro-lens corresponding to a pixel unit and has two problems. First, the size of the pixel unit of the sensor of the phone camera becomes smaller and smaller, and the imaging sensitivity and the SNR (signal noise ratio) of the sensor need to be improved, this is not benefit for image quality of pictures. Second, the micro-lens receives light in all directions for imaging of the same pixel unit. The pixel unit does not distinguish directions of the received light, so the pixel unit cannot meet a condition of the phase detection and cannot provide a basis for phase focusing.